Method for halogenation and preparing halogenated lower alkanoic acids in a flame



United States PateiitO Charles S. Cleaver, Wilmington, Del., assignor toE. I.

du Pont de Nemours and Company, Wilmington, Del., a corporation ofDelaware No Drawing. Application February 1, 1955 Serial No. 485,619

21 Claims. (Cl. 260-539) This invention relates to a new method foreffecting chemical reaction. More particularly, this invention relatesto a new process for halogenating lower alkanoic acids.

This application is a continuation-in-part of my copending patentapplication, Serial No. 319,170, filed November 6, 1952, now U. S.Patent No. 2,782,219, issued February 19, 1957.

Halogen-containing organic compounds as a class are important industrialchemicals and many preparative routes thereto are known, the most commonof which is direct halogenation. However, this technique, whilegenerally proceeding satisfactorily, in many instances is not asefficient or controllable as is desired. For instance, in the fatty acidseries simple halogenation yields first the alpha-monohalo derivative,then the alpha,alphadihalo derivative, etc. Accordingly, it is notpossible by this technique to prepare the halogenated fatty acidswherein the halogen substituents are solely on carbons far from thecarboxyl.

The lack of controllability of direct halogenation is particularlyapparent in the preparation of halogenated derivatives of functionalcompounds. For instance, in preparing halogen derivatives of carboxylicacids by direct halogenation, usually either the carboxyl function isprotected with a suitable ester or salt group or else the halogensubstituted acyl halide is prepared directly and hydrolyzed to thedesired halogenated carboxylic acid. Fi nally, direct halogenation isalways preferably and in many instances necessarily carried out underanhydrous conditions which obviously results in higher costs and greaterprocessing difficulties.

It is an object of this invention to provide a new process forhalogenating lower alkanoic acids. A further object is to provide asimple, direct method for halogenating lower alkanoic acids whileleaving the carboxyl function unchanged. A still further object is toprovide a method for halogenating lower alkanoic acids which results inrandom halogenation of the carbon chain. Another ob ject is to provide anew process for halogenating lower alkanoic acids in aqueous systems.Other objects will appear hereinafter.

These and other objects of this invention are accomplished by thefollowing process for halogenating a lower alkanoic acid which comprisescontacting halogen free-radicals of atomic number 17 to 53 and anaqueous dispersion of said lower alkanoic acid containing at least 5% byweight liquid water, with a combusting mixture having a normalcombustion wave, maintaining the aqueous dispersion of said loweralkanoic acid in intimate mixture with said halogen radicals and saidcombusting mixture in a zone thereof where the temperature is at least1500 F. measured at standard atmospheric pressure, re-

' moving the aqueous dispersion thereby obtained from contact with saidcombusting mixture before complete combustion of said lower alkanoicacid occurs, collecting the aqueous dispersion thus removed, andseparating therefrom the resulting halogenated lower alkanoic acid. -The"ice aqueous dispersion of the lower alkanoic acid after removal fromthe combusting mixture is preferably recycled into intimate mixture orcontact with said zone of said combusting mixture in the presence ofsaid halogen radicals and removed therefrom as aforesaid. This recyclingcan be repeated a number of times to complete the conversion to thedesired halogenated products.

The term aqueous dispersion as used herein includes both heterogeneousand homogeneous, aqueous, molecular dispersions, the latter being morecommonly called aqueous solutions (see pages and 423 of Washburn,Principles of Physical Chemistry, 2nd ed., McGraw- Hill, 1921). The termhalogen radical, or sometimes halogen free-radical, is likewise wellestablished in the art (see page 657, Wheland, Advanced OrganicChemistry, 2nd ed., Wiley, 1949). As this reference points out, halogenradicals are frequently referred to as atomic halogen (see pages l-19,98-100, 174-180, Waters, The Chemistry of Free Radicals, Oxford, 1948).The use of the term atomic halogen has probably become betterestablished than halogen radical since the halogen freeradicals, likethe other non-inert, gaseous, elements, are substantially the only knownfree-radicals which are single, simple, monoatomic entities. However, itis be lieved that it is more proper to refer to these as halogenfree-radicals since their properties and reaction behavior are those ofthe other free-radicals, which it seems desirable, therefore, to treatas a true generic class. As is apparent from the pages referred to inWaters, and, in fact, the entirety of this book, free-radicals are wellknown as reactive entities functioning as reaction intermediates. Ineither event whether they are referred to as halogen free-radicals oratomic halogen, it is clear that what is meant'is one atom of halogenwith its necessary free, i. e., unpaired, unshared, and untransferred,electron.

The halogen radicals necessarily present in at least the interfacebetween the said dispersion and the said zone are those of at least onehalogen of atomic number l7-5 3, i. e., chlorine, bromine, and iodine,and are generated in situ in said interface by one or both of twogeneral methods. In the first of these, ions ofthe said halogen, such asthose from a hydrohalic acid or alkali metal salt thereof, are suppliedto said interface in a separate aqueous dispersion or in the aqueousdispersion of the lower alkanoic acid reactant. Under such conditionsthe necessary combustion Zone will normally be that established by anoxidizing or reducing combusting mixture exhibiting a normal combustionwave and containing free or combined oxygen, as supplied by anoxygen-containing fuel component, including oxygen itself.

In an alternative method, the halogen radicals are supplied through useof a halogen-containing fuel component, such as the halogens themselvesin elemental form, the halogen hydrides, the halogenated hydrocarbons,or the like. In certain of these instances, particularly in the case ofthe elemental halogens, no oxygencontaining fuel component is necessarysince the elemental halogens are known to establish the necessary normalcombustion wave by direct combustion with, for instance, hydrogen.However, an oxygen-containing fuel component can'also be present inaddition to the halogen containing fuel component.

. From the foregoing, it is apparent that there are three possiblemodifications in the methods of generating the halogen radicals in atleast the interface of the aqueous dispersion of the lower alkanoic acidreactant and the combustion zone: (1) halide ions are supplied to saidinterface in a separate aqueous dispersionor in the aqueous dispersionof the lower alkanoic acid reactant, (2) a halogen-containing fuelcomponent is used in the absence of any oxygen-containing fuelcomponent; and l (3) 'ahalogen-containing fuel'component is used incomlayer itself becomes the source of heat. .zone of burning propagatesthrough the medium. The

bination with an oxygen-containing fuel component. Because of therelative lack of by-products and the easeo'f separation of the desiredhalogenated products process variation (2) is preferred. However, interms ,of the amount of total products. prepared, process variations (1)and (3) arepreferred with (1) being particularly/preferred because ofits ease of operation.

It is also Within the scope of this invention to ,combine processvariation (1) with either process variations '(2') or (3). Thus, thenecessaryhalogen radicals canbe generated at the interface between thecombustion zone and the aqueous dispersion of the lowerv alkanoic acidreactant,b'oth bysupplying halide ion thereto in separate aqueousdispersion or in the aqueous dispersionof the lower alkanoic acidreactant andflby use of a halogencontaining fuel component, either withor Without an oxygen-containing fuel component. In many instances such acombination, ispreferred since it results in a relatively higherconcentration of the halogen radicals in the said interface Withacorresponding increase in the rate of formation of the desiredhalogenated products.

The zone in which the process of this invention can be carried outincludes the said normal combustion wave itself and all areas adjacentthereto which are also at a temperature not less than about "1500 F.measured at standard atmospheric pressure. However, .such zones arisingfrom combustion of the above-defined fuel compositions are includedwithin this invention-whetheroperated at atmospheric, super-atmospheric,or sub-atmospheric pressures. In thoseinstances where anoxygencontaining fuel component is used the preferred reaction zone isat a temperature of at least 1500F. in a combusting mixture having anormal combustion wave which is propagated at a velocity of at least 30cm./sec. and most preferably at a velocity of at least 90 cm./sec.

It is to be noted that when an oxygen containing fuel component is usedthere are usually obtained in addition to the halogenated productshigher molecular weight products of increased functional order andhydroxy-substituted derivatives and, except when the halogen is iodine,hydroperoxysubstituted derivatives as described in detail in mycopending application S. N. 319,170, filed November 6,1952, now U. S.Patent No. 2,782,219, issued February 19, 1957.

The contact time of the aqueous dispersion with the above-definedreaction zone is quite critical. It obviously must uot be of suchduration as to cause completecombustion of the lower alkanoic acidreactant, i. e., to raise the average temperature of the entire aqueous,dispersion of the lower alkanoic acid reactant to the combustiontemperature of the said reactant and, of course, the products therefromobtained in the process. Preferably, the contact time will be of suchduration that the average temperature throughout the said aqueousdispersion will not reach the boiling point of the water component underthe pressure being used. In the preferred operating conditions, thereaction or contact time will range from 0.00001 to 5.0 seconds, andnormally from 0.0001 to 1.0 second. The most preferred and mostgenerally used contact times lie within the range 0.00l-0.250 second.

In the foregoing description of this invention, many terms familiartothe combustion art have been used.

These are adequately described in greater detail in many .in it ispointed out that in a combustion process the flow of heatfrom the.ignition source initiates chemical reaction in an adjacent layer of theexplosive medium. so that the In this way a zone constitutes a waveandis referred toas a combustion mesa-s22,

transformation associated with different reaction mechanisms. :This area.is extremely thin and at atmospheric also be used.

This invention is further illustrated, but not lirnited, by thefollowing examples, in which the parts are by weight except for the datagiven. on the various fuel compositions which are. in parts by volume.

.Example. I

A 2% aqueous acetic acid solution containing about 5.5% of sodiumchloride was passed in'the form of a cylindrical stream about 0.022 inchin diameter at a rate ofabout 50 parts per minute through the tipportion of the inner cone (i. e., twice through. the combustion wave) ofa l/ 1 hydrogen/ oxygen flame burning at atmospheric pressure (maximumtemperature about 4150-4350" F.

and normal combustion .wave propagation velocity of aboutf600cm./sec.),-as established from a commercial handtorch with a nozzlehaving an orifice of 6570 mils inside diameter. The total contact timesof the aqueous solution were with (a) the total fiamecross-section about3 millisec., i. e., 0.003 sec., ([2) the zone of at.least 1500 F. about4-5 .millisec., i. e., 0004-0005 sec., and

(c) the normal combustion wave about 0.01 milliseo, i. e., 0.00001 .sec.The input rate of each of the burner gases was. maintained at about 3liters per minute. During the passage .of the solution through theflame, there was no evidenceof the characteristic yellow fiame color ofsodium. The input temperature of. the aqueous acetic.acid/sodiumchloride solution was about -80 F. and

therexit. temperature of :the. solution from the flame zone was.about.95.F.

After passage through the :llame, the aqueous reaction mixture wascollected directly in a vessel cooled in an ice/waterv bath and thesolution then recycled through the flame and normal combustion wave aspreviously described for a total of ten cycles. The organic products .inthe resultant reaction mixture were extracted with diethyl ether in acontinuous counter-current liquid/liquid extractor oveina period :of. l8hours and the ether extract separated and dried over anhydrous magnesiumsulfate.

The etherwas removed from the extract by distillation under atmosphericpressure and the large quantity of recovered acetic acid removed fromthe mobile, oily liquid residue by evaporation in a stream of nitrogenat about 50-60 C. leaving as a residue a liquid mixture of chloro--acetic acid, succinic acid, hydroperoxyacetic acid, and glycolicacid.-By chromatographic separation and identification techniques, inthemanner of Marvel and Rand, J. Am. Chem. Soc. 72, 2642 (1950), on achloroform .solution' thereof, the: mixture was found to contain 76.8%

chloroacetic acid, 5;4% succinic acid, 10.7% hydroperoxyacetic acid, and7.1% of glycolic acid, all exhibiting characteristic peak elutionvolumes for the respective acids, identical with those exhibited byauthentic samples .of the various acids prepared in conventionalfashion.

Example 11 -The tsynthesis -described in. Example I was repeated,

substituting for the acetic acid/sodium chloride solution a 4% aceticacid solution containing about 1.9% sodium bromide. There was obtained aliquid oily mixture of carboxylic acids which by the samechromatographic separation and identification techniques was found toconsist of over 95% bromoacetic acid, with minor quantities of succinic,glycolic, and hydroperoxyacetic acids, all exhibiting characteristicpeak elution volumes identical with those exhibited by authentic samplesof the respective acids prepared in conventional fashion.

Example [11 The synthesis described in Example I was repeated,substituting for the acetic acid/sodium chloride solution a 4% aceticacid solution containing about 0.3% sodium iodide. There was obtained anoily, liquid carboxylic acid product which by the same chromatographicseparation and identification techniques was found to consistsubstantially quantitatively of iodoacetic acid, exhibiting acharacteristic peak elution volume identical with those exhibited by anauthentic sample of the acid prepared in conventional fashion.

Example IV In the manner described in Example I, a 2% aqueous aceticacid solution was passed through the tip portion of the inner cone of a4/3 hydrogen/chlorine flame burning at atmospheric pressure for a totalof ten cycles. The products were isolated and the recovered acetic acidremoved as described in detail in Example I. There was-thus obtained anoily, carboxylic acid product which by the same chromatographicseparation and identification techniques was found to consist almostquantitatively of chloroacetic acid, exhibiting a characteristic peakelution volume therefor identical with that exhibited by an authenticsample of the acid prepared in conventional fashion.

Substantially identical results were achieved using a 4% aqueous aceticacid solution and a 1/1 hydrogen/ chlorine flame.

Example V In the manner described in Example I, a 4% aqueous acetic acidsolution was passed through the tip portion of the inner cone of a 1/2methyl chloride/oxygen flame burning'at atmospheric pressure for a totalof 'ten cycles. The products were isolated and the recovered acetic acidremoved as described in detail in Example I. The resultant oily,carboxylic acid product was found by the same chromatographic separationand identification techniques to consist almost quantitatively ofchloroacetic acid exhibiting a characteristic peak elution volumeidentical with that of an authentic sample of acid prepared inconventional fashion.

Substantially identical results were obtained using a 1/1 methylchloride/ oxygen flame Example VI In the manner described in Example I a2% aqueous acetic acid solution was passed through the tip portion ofthe inner cone of a 3.0/3.0/0.1 hydrogen/oxygen/ hydrogen chloride flameburning at atmospheric pressurefor a total of ten cycles. The resultantorganic products were isolated and the recovered acetic acid separatedtherefrom as described in detail in Example I. The oily mixture ofcarboxylic acid products was found by the same chromatographicseparation and identification techniques to consist of 77.0%chloroacetic acid, 0.8% succinic acid, 18.0% hydroperoxyacetic acid, and4.2% glycolic acid, all exhibiting characteristic peak elution volumestherefor identical with those of authentic samples of the resultantacids prepared in conventional fashion.

The process of this-invention requires intimate contact between anaqueous dispersion of the lower alkanoic acid reactant and the zone of acombusting mixture which is at a temperature of at least 1500 F., saidmixture having a normal combustion wave. This essential process step canbe achieved by moving the aqueous dispersion relative to the said zone,or vice vers'a, or by both of such means. The most convenient of thethree means, from the standpoint of the equipment and handling thereof,involves the movement of the aqueous dispersion of the lower alkanoicacid reactant relative to the said zone. By suitable means, such aspumps, storage vessels, pressure regulators, flow controllers, and othermeans known in the art for measuring and handling gaseous, liquid, orsolid components, the fuel compositions can be supplied to a suitableapparatus equipped with ignition means in controlled amounts so as tomaintain the requisite zone having a standing combustion wave.

The aqueous dispersion of the requisite lower alkanoic. acid reactant orreactants can be brought into the necessary zone, including actualcontact with the said normal combustion wave, by many means. Forinstance, the aqueous dispersion can be in the form of a homogeneousmolecular dispersion, i. e., an aqueous solution, and the said aqueousdispersion can be brought into the necessary position relative to thestanding normal combustion wave in a single stream, multiple streams,flowing sheets, aerosols, sprays, or in the form of grosser dropletssuch as are obtained by suitably pressuring the said aqueous dispersionthrough a diaphragmof controlled porosity, such as the conventionalsintered glass disks.

The normal combustion wave and the zone proximate thereto of therequisite temperature can likewise be in any shape or form as determinedby the shape or form Reynolds numbers for the elements of the fuelcomposition.

One of the alternative procedures, i. e., causing the combustion wave tomove relative to the aqueous dispersion of the lower alkanoic acidreactant can be carried out using a spray or aerosol of the said-aqueousdispersion and counter-currently passing in bubble-form the necessarycombustion components and effecting ignition and combustion through thecombustible gas bubbles resulting in explosion of the said mixture withthe forma tion of the necessary normal combustion wave. Obviously thesame effects can also be achieved by metering the necessary combustioncomponents separately either counter or cocurrently provided that theirmutual interface occurs in the ignition zone.

Although in the foregoing, specific embodiments as to the apparatusrequirements and suitable means for carrying out the process of thisinvention have been given, it is to be understood that the presentinvention is by no means thus limited. Obviously, other types ofapparatus and means for combining the various elements disclosed hereincan be employed for effecting the process of this invention. The onlyrequirement as to this portion of the invention is that an aqueousdispersion of the lower alkanoic acid reactant or reactants specificallyinvolved be brought into intimate contact with the at least 1500 F. zoneof a combusting fuel composition having a normal combustion wave, andwherein halogen radicals are being generated at least at the interfaceof said dispersion and said zone.

As indicated previously, the necessary normal combustion wave and insitu halogen radical generation in the interface between the combustionzone and the aqueous dispersion of the lower alkanoic acid reactant canbe effected in several ways. In one modification oft The combustionwaves or flames can also i be laminar or turbulent, depending on thewell known -like. which can be used as fuel components include methylalcohol, acetone, diethyl ether, ethyl acetate, methane, benzene,cyclohexane, cylohexene, butadiene, acetylene,

the. p ocess oth. are achi ve y u lnga el s nxtue comp nent in h pre enor ab n f an oxy encontainiuaf el mpo nt. Sui ab a o en e mpositionsinclude the elemental halogens themselves, i. e., Qhlorine, bromin .andiodine in combination with a reactiye nonroxygen-containing fuelcomponent, such as hydrogen, ,andthe hydrohalides and organic halidessuch as thealkylhalide te.gs hy hl ri e, t oxysencontainingfuelcomponent, such as oxygen orair.

.MQSLo nyenien-tly the halogen is supplied to the inter- .face inionicform in solution in separate aqueous dispersion or in that of the loweralkanoic acid reactant. Suitable wate ol hlesour es ,of the ion h l enhalides, include th l g h a og n hydr d th hydrog h id and th -Wer-sombl s l ,especiallythe water soluble metal halide salts, such asthose of the alkali and alkaline earth rnetals, e. g., hydrosemchlo idpo a s um omi l hium hlori magn sium iodide, c l ium br i a um h o i anthe: lik

Underthese conditions the normal combustion wave will generally beobtained by combusting any combustible -fuel withoxygen in an amountbetween the lower and upper explosive limits for the particular fuel.

position, that is the fuel/oxygen composition must be combustible.

Suitable-examples of the said fuel compositions, wherein the .requisiteoxygen is initially present in combined form, i. e., atomic form, arewell known in the art.

vA particularly outstanding class of this type of selfeontainedcombustible mixture will be found amongst the nitrosubstituted organiccompounds, particularly those containing a relatively high proportion ofmtro groups per carbon atom. Suitable specific illustrations of thistype of compounds include nitromethane, t r1 nitrotoluene, and the,like. Becau e of. t e r grea e l bil ty. gen lly at low cost, andparticularly readier handleability and greater ease of control, thosefuel compositions are preferred wherein the. requisite oxygen issupplied in uncomhined form, i. e.,.as molecular oxygen, eitherseparately or in admixture with the combustible fuel component orcomponents being used. The necessary combustible fuel component orcomponents which can be used are many and varied [see, for instance,Walker et al., J. Am. Chem. Soc. 74, 3769 (1952)]. For instance, all thehydrocarbons, both saturated and unsaturated, including polyunsaturated,aliphatic, aromatic, alkaromatic, araliphatic,

,cycloaliphatic, and like hydrocarbons can be used. The

heterocyclic compounds and functionally substituted hydrocarbons andheterocyclic compounds can also be used such as alcohols, phenols,ethers, esters, ketones, and the Suitable specific illustrations of suchcompounds ethane, and the like. The simpler organic and even in-.organic compounds can also be used as fuel components, for instance,cyanogen, hydrogen cyanide, hydrogen, and

the like.

For obvious reasons, the relatively low cost, commercially availableliquid or gaseous hydrocarbons, usually mixed, constitute a preferredsourceof the necessary normal combustion wave. The various fuel oils tems ves, Whether p rified o not, als onst t te a P ef re -sou tth -c mustlonwav .Obriouslnflre mo highly e ne .hy r ea on nuchs s:ga o nronthe l k s o s i te an e l nt our ofthe omhustion wave. The solidfuels including the various wood-residues, coal and peat products,andlike allied, industrially available, usually low cost materials,canalso be: used'as fuel components. 7

ecause of increased handling ease and thejlow cost availability of many:such compositions, the wholly gaseous. fuel components are preferred.Suitable examples of these include natural gases, including producergas, and other types normally, encountered in the natural state frompetroleum operations; commercially produced combustible gases such asthe so-called water, carbureted water, synthesis, blue, mixed coal,anthracite producer, coke oven, blast furnace, city gases, and-the'li-ke; liquid petroleum hydrocarbons (LPH), which; are commerciallyavailable under reasonably low pressures in'liquid form easilyexpandable at atmospheric pressures to the gas phase and which usuallycontain various saturated and unsaturated hydrocarbons in the 2 to 4carbon range, such as propane, butane, isobutane, ethane, propylene, andthe like, normally in mixtures; as well as the previously mentionedhydrogen and carbon monoxide which, particularly the latter, appear invarying proportions in most of the above referred to. commerciallyproduced gases of the type of water gas,.and thelike.

The oxygen necessary with most of the above detailed fuel components forproducing the necessary combustion wave for use in the present inventionand which is preferably supplied .in the form. of molecular oxygen, i.e., uncombinedcan besuppliedinpure form, if desired,.or equally Well inthe form of air, the inertdiluentsof which have no untoward effect onthe reaction. From a cost standpoint, it is obviously preferred tosupply the oxygen in the form of air. Other diluents can. be present inthe oxygen as well, including, for example, such materials as carbondioxide, rare gases and; the like. 'Other oxygen sources whichsupportcombustion can also be used, such as the oxides of nitrogen, e.g, nitrousv oxide, nitrogen dioxide, and the like.

Still another modification ofthe process is the simultaneous use ofhalogen-containing and oxygenpontaining fuel components either alone orin combination withauy of the just described fuel components. Suitablecornbustible halogen-containing fuel components include elementalhalogens, halogen hydri'des, halohydrooarbons, especially of less thansix carbons permolecule, and the like. Thus, suitable illustrative fuelcompositions of this type include mixtures of hydrogen, chlorine, andoxygen; hydrogen, iodine, and carbon monoxide; hydrogen, methane, andbromine; hydrogen, oxygen, and methyl chloride; hydrogen chloride andoxygen; and the like.

It has been found essential in carrying out this process that theaqueous dispersion contain at least 5% liquid water. The upper limit ofthe amount of water really is infinite, since this is only controllingas to the amount of new products formed as a function of time.Reasonable requirements of time and operating costs indicate an upperpractical limit of water concentration-to be about 1000 parts per partof simple organic reactant or mixtures thereof, i. e., 99.9%liquid-water.

Lhe foregoing examples illustrate specifically some of the preferredembodiments of the process of this invention, e. -g., using acetic acid,to produce halogenated, hydroxy andhydroperoxy substituted monoandpolycarboxylic acids. However, the invention isnot-tobe limited therebyand there are alsoaincluded' within the present invention thehalolalkanoioacids as obtained from the lower alkanoic acids, such as;alphabeta-. and gamma-chlorobutyric acids from butyric acid; :and. thelike.

Asmany apparently widely differentiembodiments of this invention may bemade without departing fromathe spirit andscope thereof, it-is1totbeunderstood-that this 9 invention is not limited to the specificembodiments thereof except as defined in the appended claims.

The embodiments of the invention in which an exclusiveproperty orprivilege is claimed are defined as follows.

I claim:

1. In a process for preparing polyfunctional organic compounds whereinan aqueous dispersion of a lower alkanoic acid is contacted with a fuelcombusting mixture having a normal combustion wave in a zone thereofwhere the temperature is at least 1500 F. measured at standardatmospheric pressure, the improvement which comprises contacting andmaintaining halogen free-radicals of atomic number 17 to 53 in intimatemixture with an aqueous dispersion, containing at least liquid water, ofsaid lower alkanoic acid and with said combusting mixture in a zonethereof where the temperature is at least 1500 F. measured at standardatmospheric pressure, removing the aqueous dispersion thereby obtainedfrom contact with said combusting mixture before complete combustion ofsaid organic compound occurs, collecting the aqueous dispersion thusremoved, and separating therefrom as a resulting product the halogenatedlower alkanoic acid having halogen as an additional functional group.

2. In a process for preparing polyfunctional organic compounds wherein aliquid water solution of a lower alkanoic acid is contacted with a fuelcombusting mixture having a normal combustion wave in a zone thereofwhere the temperature is at least 1500 F. measured at standardatmospheric pressure, the improvement which comprises contacting andmaintaining halogen freeradicals of atomic number 17 to 53 in intimatemixture with a liquid water solution of said lower alkanoic acid andwith said combusting mixture in a zone thereof where the temperature isat least 1500 F. measured at standard atmospheric pressure, removing theliquid water solution thereby obtained from contact with said combustingmixture before the temperature of the water solution is raised to theboiling point of the water component thereof, collecting the liquidwater solution thus removed, and separating therefrom as a resultingproduct the halogenated lower alkanoic acid having halogen as anadditional functional group.

3. Process as set forth in claim 2 wherein the liquid water solutionthus removed is recycled into intimate contact, in the presence of saidhalogen free-radicals, with said fuel combusting mixture in said zonethereof where the temperature is at least 1500 F. measured at standardatmospheric pressure.

4. In a process for preparing polyfunctional organic compounds wherein aliquid water solution of a lower alkanoic acid is contacted with a fuelcombusting mixture having a normal combustion wave in a zone thereofwhere the temperature is at least 1500 F. measured at standardatmospheric pressure, the improvement which comprises contacting andmaintaining a liquid water solution of said lower alkanoic acid whichcontains halide ions of a halogen of atomic number 17 to 53 in intimatemixture with an oxygen-containing fuel combusting mixture in a zonethereof where the temperature is at least 1500 F. measured at standardatmospheric pressure, removing the liquid water solution therebyobtained from contact with said oxygen-containing fuel combustingmixture before the temperature of the water solution is raised to theboiling point of the water component thereof, collecting the liquidwater solution thus removed, and separating therefrom as a resultingproduct the halogenated lower alkanoic acid having halogen as anadditional functional group.

5. Process as set forth in claim 4 wherein the liquid water solutionthus removed is recycled into intimate contact, in the presence of saidhalide ions, with said oxygen-containing fuel combusting mixture in saidzone thereof where the temperature is at least 1500' F.'meas ured atstandard atmospheric pressure.

6. In a process for preparing polyfunctional organic compounds wherein aliquid water solution of a lower alkanoic acid is contacted with a fuelcombusting mixture having a normal combustion wave in a-zone thereofwhere the temperature is at. least 1500 F. measured at standardatmospheric pressure, the improvement which comprises contacting andmaintaining a liquid water solution of said lower alkanoic acid, whichcontains an alkali metal halide of atomic number 17 to 53,.in intimatemixture with an oxygen-containing fuel combusting mixture in a zonethereof where the temperature is-at least 1500 .F. measured at standardatmospheric pressure, removing the liquid water solution therebyobtained from contact with said oxygen-containing fuel combustingmixture before the temperature .of the water solution is raised to theboiling point of the water component thereof, collecting the liquidwater solution thus removed, and separating therefrom as a resultingproduct the halogenated lower alkanoic acid having halogen asanadditional functional group.

7. Process for halogenating a lower alkanoic acid as set forth in claim6 wherein said alkali metal halide is sodium chloride. 1

8. Process for halogenating a lower alkanoic acid as set forth in claim6 wherein said alkali metal halide is sodium bromide. I

9. Process for halogenating a lower alkanoic acid as set forth in claim6 wherein said alkali metal halide is sodium iodide. 1 Y X 10. Processas set forth in claim 6 wherein the liquid water solution thus removedis recycled into intimate contact, in the presence of. said alkali metalhalide, with said oxygen-containing fuel'combusting mixture in said zonethereof where the temperature is at least 1500 F. measured at standardatmospheric pressure.

11. In a process for preparing polyfunctional organic compounds whereina liquid water solution of a lower alkanoic acid is contacted with afuel combusting mixture having a normal combustion wave in a zonethereof where the temperature is at least 1500 F. measured at standardatmospheric pressure, the improvement which comprises contacting andmaintaining a liquid water solution of said lower alkanoic acid inintimate mixture with a halogen-containing fuel combusting mixture,having a normal combustion wave and wherein the halogen is of atomicnumber 17 to 53, in a zone thereof where the temperature is at least1500 F. measured at standard atmospheric pressure, removing the liquidwater solution thereby obtained from contact with said halogencontainingfuel combusting mixture before the temperature of the water solution israised to the boiling point of the water component thereof, collectingthe liquid water solution thus removed, and separating therefrom as aresulting product the halogenated lower alkanoic acid having halogen asan additional functional group.

12. Process as set forth in claim 11 wherein the liquid water solutionthus removed is recycled into intimate contact with saidhalogen-containing fuel combusting mixture in said zone thereof wherethe temperature is at least 1500 F. measured at standard atmosphericpressure.

13. Process for halogenating a lower alkanoic acid as set forth in claim11 wherein said halogen-containing fuel combusting mixture is achlorine-containing fuel combusting mixture.

14. Process for halogenating acetic acid which comprises contactinghalogen free-radicals of atomic number 17 to 53 with an aqueousdispersion, containing at least 5% liquid water, of acetic acid and witha combusting mixture having a normal combustion wave, maintaining saidaqueous dispersion in intimate mixture with said halogen radicals andsaid combusting mixture in a zone thereof where the temperature is atleast 1500 F.

mates-teas measured at standard atmospheric pressure, removing theaqueous dispersion therebytobtained from contact :with said combustingmixtureubefore the vtemperature of the aqueous dispersion; is raised; tothe boiling point of-the water component thereof, collecting the aqueousdispersionsthuszremoved, anduseparatingtherefrom a haloacetic acids-asthe; resultingzproduct.

15. Process fonhalogenatingacetic acid which comprisescontactinguawatersolution ofacetic acid/and an alkalimetal halidewherein the halogen is of atomic number 17 to 53 withtan.oxygen-containing fuel combusting mixture havinga normal; combustionwave, maintaining said- .-water solution-in intimate: mixture with saidcomhustingmixture in aizonefthereof where-the temperature is at least1500 F.'measur;ed ati-standard atmospheric pressure, removing the watersolution thereby obtained from. contact :with said combusting mixturebefore the temperature. ofsthe water solution is raised to the boilingpoint of the water component thereof, collecting-thewater solution thusremoved, and separating-therefrom a haloacetic acid as the resulting:product.

16. Process for halogenating aceticacidhawset forth in claim 15 whereinsaid alkali metal halide. is sodium chloride. I

17. Process for halogenating acetic acid as.:set' forth in claimh15wherein saidalkali metal halideist'sodium bromide. v I

18. Process for halogenating acetic acid assetforth in claim l5-whereinsaid alkali metal halide=is-=sodium iodide; a

19. Process for halogenating acetic acid which -comvprises contacting awater .solutionof acetic acid: with a halogen-containing fuelcombustingmixture-having a normal' combustion :wave and wherein the'halogenis of atomic number 17' to 53, maintaining said-solution inintimate mixture with said halogen-containing fuel combusting mixture'ina zone thereof where the tempera-ture is at .least. 1500 F; measuredatstandardoatmospheric 12 pressure, removingthe water solution therebyobtained from contact with said combusting mixture before thetemperature of the water solution is raised to-the boiling :point of the:water component thereof, recycling the water solution thus removed intointimate contact in said zone with said halogen-containing fuelcombusting mixture and removing and collecting, as aforesaid, the watersolution thereby obtained, and separating therefrom a haloacetic acid asthe resulting product.

20. Process for halogenating acetic acid as set forth in claim 19wherein said halogen-containing fuelcombusting mixture is achlorine-containing fuel comhusting mixture.

21. Process for halogenating acetic acid which comprises contacting awater solution of acetic acid and a sodium halidewherein the halogen isof atomic number 17 to 53 with an oxygen-containing fuel combustingmixture having a normal combustion wave, maintaining said water:solution in intimate mixture with said oxygen-containing fuelcombusting mixture in .a zone thereof wherethe. temperature isat ,leastl-500 F. measured at standard atmospheric pressure, removing the watersolutionthereby obtained from contact with said combusting mixture,before the temperature of the .water solution is raised to the boilingpoint of the water component thereof, recyclingithe .water solution thusremoved into intimate contactin saidzone with said combusting-mix-Hireimthetpresenceof said sodiumthalide and removing and ollecting, ,asaforesaid, the watersolution thereby obtainedrand separating, therefroma haloacetic zaci'd -as th resultin p oduct.

ReferencestCited in the file of thispatent UNITED. STATES PATENTS YjjLadd Nov. 1' 8,"1'-95-2 Sonia et al. Apr. 6, 1 954

1. IN A PROCESS FOR PREPARING POLYFUNCTIONAL ORGANIC COMPOUNDS WHEREINAN AQUEOUS DISPERSION OF A LOWER ALKANOIC ACID IS CONTACTED WITH A FUELCOMBUSTING MIXTURE HAVING A NORMAL COMBUSTION WAVE IN A ZONE THEREOFWHERE THE TEMPERATURE IS AT LEAST 1500*F. MEASURED AT STANDATDATMOSPHERIC PRESSURE, THE IMPROVEMENT WHICH COMPRISES CONTACTING ANDMAINTAINING HALOGEN FREE-RADICALS OF ATOMIC NUMBER 17 TO 53 IN INTIMATEMIXTURE WITH AN AQUEOUS DISPERSION, CONTAINING AT LEAST 5% LIQUID WATER,OF SAID LOWER ALKANOIC ACID AND WITH SAID COMBUSTING MIXTURE IN A ZONETHEREOF WHERE THE TEMPERATURE IS AT LEAST 1500*F. MEASUERD AT STANDATDATMOSPHERIC PRESSURE, REMOVING THE AQUEOUS DISPERSION THEREBY OBTAINEDFROM CONTACTG WITH SAID COMBUSTING MIXTURE BEFORE COMPLETE COMBUSTION OFSAID ORGANIC COMPOUND OCCURS, COLLECTING THE AQUEOUS DISPERSION THUSREMOVED, AND SEPARATING THEREFROM AS A RESULTING PRODUCT THE HALOGENATEDLOWER ALKANOIC ACID HAVING HALOGEN AS AN ADDITIONAL FUNCTIONAL GROUP.